The “BeeMonitor” project

Beekeeping is a time consuming hobby, it’s not so easy as it sounds. Making sure the bees are healthy takes a lot of knowledge and experience.

Adding sensors to a beehive helps the beekeeper to monitor the hive and take action when things are not as expected.

Therefor I decided to make my own “BeeMonitor”. Starting with the electronics, connecting our hives to the internet!

The BeeMonitor with sensors

The technical side:

The BeeMonitor is a “battery powered wireless datalogger”. It’s a compact controller with user-changeable dipswitches, RGB led, buzzer, “plug & play” RJ12 connectors designed for different sensors combinations and is capable to carry 2 different wireless modules, a RFM69W for use in a private network or the RFM95W to connect to an LPWAN IoT network (LoRaWAN) on sub-gigahertz radio bands. Powered by 2 AAA battery’s, operating on 3V the”BeeMonitor” only consumes 35nA in sleep the making the battery’s last for years! Great, isn’t it?

Transmitted messages are received by a gateway, processed and stored in a database. Data can be shown on a website and even in online “live” graphs depending on the needs.

BeeMonitor with custom front

For example, some temperature & humidity data from one of our beehives:

Battery life:

The prototype has been up & running, collecting data for about 2 months now. So far the battery voltage has dropped from 3.17V to 3.12V without any (low power) software optimisation. Even without the battery will keep the BeeMonitor up & running for a very long time, all the way down to 1.9V. That’s when the voltage reaches the minimum operation voltage for some of the hardware.

Power consumption:

Measuring one wake-up cycle (about 2 seconds) gives a clear overview of the power consumption of the hardware. A short description of how things work here (reference: 1 mV = 1 mA):

  • 0 s: External input, interrupt or timer waking up a part of the hardware (50 nA)
  • 250 ms: Power enabled to other hardware (1.8 mA)
  • 320 ms: Microcontroller startup, bootloader (3.5 mA)
  • 1.7 s: Microcontroller running program, reading sensors, processing
  • 1.82 s: Sending message (50 mA)
  • 1.83 s: Waiting for ACK from gateway (18 mA)
  • 1.85 s: Blink green led (4 mA)
  • 2 s: Powerdown (35 nA)

This graph makes clear I need to optimize the bootloader, because it takes 1.38 s! Thats way to long for battery powered hardware.

Future plans:

There are some improvements needed such as an optimized bootloader, optimized software for better battery life, ..

September 2017: The prototype has been upgraded, read more about the plans & upgrades here.